The invention is directed to a dual-chamber package comprising a substantially dimensionally stable outer container (1) for receiving liquid or pasty contents and provided with a dispensing valve (2), and an inner container disposed within the outer container (1) for receiving a pressurized gas such as pressurized air, nitrogen or the like, wherein the inner container (3) is designed as a flexible bag and wherein the dispensing valve (2) comprises a dispensing tube (17) disposed within a valve body (14) for movement from a closed position to an open position, and vice versa.
Such dual-chamber packages are generally known, for example from EP-A-0181116, EP-A-0033377 or GB-B-1425854.
The known dual-chamber packages exhibit the common feature that the inner bag includes chemical agents for producing pressurized gas which are activated when a predetermined period of time has elapsed. To this end, for instance in accordance with the proposal of EP-A-0033377, the inner bag includes means for delaying the chemical reaction for producing pressurized gas.
It appears obvious that the mentioned proposals require a considerable design effort. Furthermore, the operational safety is not all that could be desired. Finally, the expenses are additionally increased by the use of chemical agents for producing an adequate quantity of pressurized gas within the inner bag. Due to this fact the ecological compatibility of these known designs is extremely doubtful. Therefore the dual-chamber packages of the specified kind have not been widely accepted for practical use.